In a digital broadcasting system, a video/audio signal is compressed using a digital signal compression technique, and a stream (a transport stream) obtained by subjecting video/audio digital signals in a plurality of programs to time-division multiplexing is broadcast. On the other hand, a broadcasting receiver that receives such digital broadcasting selects one of a plurality of channels in digital broadcasting received through an antenna by a tuner, selects one of a plurality of programs included in the one channel by demultiplexing processing, and decodes a digital signal on the selected channel to output a video/audio signal.
When terrestrial wave digital broadcasting is received, a usage way in which an indoor antenna is used is assumed. However, it is expected that a receiving error occurs because a sufficient quality of a receiving signal is not obtained depending on the positional relationship among the indoor antenna, a window of a house, and a transmitting station. Therefore, it is considered that a retransmitter (repeater) is placed at the window of the house, for example, to amplify a digital broadcasting wave received by an antenna of the retransmitter and emit the amplified digital broadcasting wave toward the indoor antenna of the digital broadcasting receiver.
When such retransmission is made, however, oscillation easily occurs by coupling an input and an output. Therefore, the distance between a receiving antenna and a transmission antenna must be increased, thereby increasing the size of the retransmitter. Further, it is considered that retransmission is made at a frequency different from a broadcasting frequency. However, a digital broadcasting signal is fed with service information added thereto. When the frequency is changed by retransmission, the actual receiving frequency and the frequency of the service information do not coincide with each other on the side of the receiver. Consequently, the service information must be rewritten and retransmitted by the retransmitter, so that the configuration becomes complicated, resulting in increased cost.
In view of the foregoing circumstances, an object of the present invention is to provide a retransmitter and a digital broadcasting receiving system that can suitably make retransmission without changing a frequency.